The advent of virtualization technologies for computing resources has provided benefits with respect to managing large-scale computing resources for many customers with diverse needs. In addition, virtualization technologies have allowed various computing resources or computing services to be efficiently and securely shared by multiple customers. For example, virtualization technologies may allow a single physical host (e.g., a single physical computing machine) to be shared among multiple customers by providing customers with one or more computing instances hosted by the single physical host using a hypervisor. A computing instance may be a guest machine acting as a distinct logical computing system that provides a customer with the perception that the customer is the sole operator and administrator of a given virtualized hardware computing resource.
A request to launch a computing instance may entail identifying available computing resources (e.g., a computing slot in a hypervisor) on which the computing instance may be executed. For example, one or more physical hosts (e.g., server computers or physical computing machines) may be queried to determine whether sufficient computing resources exist on a physical computing machine to launch and execute a computing instance and whether a physical host meets additional specified criteria (e.g., disaster mitigation criteria, licensing criteria, etc.) for the group of physical hosts. In a case where a physical host is identified as having computing resources available to execute the computing instance and meeting the specific criteria, the computing instance may be launched on the physical host, and a customer may be notified that the computing instance has been launched. Furthermore, a computing instance may be terminated by a customer when the computing instance is not being used in order to avoid additional charges for the time the computing instance is executing.